1. Field of the Invention
This invention relates to knee braces or orthoses intended primarily for stabilization of the human knee joint, e.g. a post-operative knee or an injured knee joint having a ligament deficiency or the like. Such orthoses are intended to stabilize the knee joint by protecting it against certain types of harmful motion such as rotational or twisting motion, hyperextension, etc. while nevertheless permitting a degree of normal motion adequate for ordinary activities and even for athletics.
2. Description of the Prior Art
It has long been recognized that patients who have had knee surgery or have suffered knee injuries or damage can benefit significantly from a leg-engaging brace which protects the knee joint from re-injury or further damage by preventing unnatural movements without hindering movements needed for walking, running, etc. Typically, these braces or orthoses are provided with a thigh-engaging component and a calf-engaging component, with side bars or support arms located on both sides of each leg to connect these two components. To permit normal bending of the knee or swinging back and forth of the lower leg, the support arms or side bars have pivot devices which act much like hinges but in addition define a useful range of motion about a horizontal axis through the knee. Further support for the knee is provided by elastic straps which encircle or partially encircle the leg and are attached at various locations on the brace. Convenient fastening and unfastening of these straps is typically provided with modern synthetic fabric devices such as VELCRO fasteners, which are made up of an engagement means comprising a great multitude of tiny plastic loops or hooks and/or a raised nap, so that mated fabric surfaces will engage each other.
In recent years, the development of these braces has been progressing very rapidly, with the result that the patent literature in this field has become extremely voluminous. It has become difficult to cover, in any discussion of reasonable length, even a representative sampling of relevant patent disclosures.
Despite the growth of knowledge and skill in this art, problems for the wearers of knee orthoses and for their physicians and therapists remain to be solved. It is particularly difficult to design a knee brace which will prevent hyperextension, undue twisting of the knee joint, etc. and yet will be simple, light in weight, non-slipping, easy to manufacture, comfortable to wear, and capable of permitting great ease of normal motion in a any desired direction, e.g. in strenuous athletic contests. Knee braces which provide all the desired protection with reasonable comfort and good freedom of normal motion tend to be heavy or complex in structure. The simpler braces, on the other hand, may fail to provide adequate protection against certain unnatural movements such as hyperextension. Alternatively, the simpler devices may be subject to slippage, twisting or rotation movement about the vertical axis of the leg. Moreover, all modern knee braces intended for athletic use must accommodate major dynamic changes such as the changes in muscle shape and volume which occur through a very wide range of motion.
Because of the extensive development of this art particularly during the last five to ten years, any list of patent references is necessarily incomplete, even if intended as only a sampling of the available patent literature, but the following list can serve as an introduction to the modern, relatively sophisticated types of knee orthoses.
______________________________________ 3,669,105 (Castiglia) June 13, 1972 4,361,142 (Lewis et al) Nov. 30, 1982 4,372,298 (Lerman) Feb. 8, 1983 4,493,316 (Reed et al) Jan. 15, 1985 4,554,913 (Womack et al) Nov. 26, 1985 4,556,053 (Irons) Dec. 3, 1985 4,565,190 (Pirmantgen et al) Jan.21, 1986 4,624,247 (Ford) Nov. 25, 1986 4,686,969 (Scott) Aug. 18, 1987 ______________________________________